In a balanced three-phase system, is the neutral often omitted in distribution and transmission wye circuits?

In a balanced three-phase system, is the neutral often omitted in distribution and transmission wye circuits?

• A. True
• B. False
• C. Not applicable
• D. Sometimes

Answer: (A)

When three-phase currents are balanced, the currents in the three lines are 120 degrees apart and their vector sum at the neutral point is zero. That means no current flows in the neutral conductor, so the circuit can be completed with just the three line conductors in distribution and transmission wye circuits. In practice, loads aren’t perfectly balanced and a neutral may still be present for grounding or to carry unbalanced current, but under balanced conditions the neutral is often omitted.

When three-phase currents are balanced, the currents in the three lines are 120 degrees apart and their vector sum at the neutral point is zero. That means no current flows in the neutral conductor, so the circuit can be completed with just the three line conductors in distribution and transmission wye circuits. In practice, loads aren’t perfectly balanced and a neutral may still be present for grounding or to carry unbalanced current, but under balanced conditions the neutral is often omitted.